It is known that a color image can be formed by imagewise exposing light-sensitive layers containing yellow, magenta and cyan couplers (i.e., yellow dye-forming coupler, etc.) and processing the exposed layers with a color developing agent whose oxidized product is capable of coupling with the couplers to form the respective dyes. According to this color image formation system, it is important that a light-sensitive material having a silver halide coverage as small as possible be developed to efficiently form a color within a limited development time.
Efficient color formation requires rapid progress of silver halide development and complete development of silver halide to be developed without any residual, a so-called "dead grain". It is also important that the thus produced oxidation product of a color developing agent should react with a color coupler without being wasted. It is known that these requirements can be met by using silver halides having a high developing speed or silver halides having a high rate of development, i.e., a low dead grain rate, and, in fact, silver chloride or silver chlorobromide emulsions can sometimes be employed to achieve this effect. In cases when such a silver halide cannot be used, e.g., in high-speed photographing, it is also known to increase the silver halide coverage with respect to a color coupler to thereby accelerate or ensure color formation. Use of couplers having a high rate of coupling is furthermore effective. It is also beneficial to heighten the developing activity of a color developing solution per se.
In an attempt to increase the rate of color development of color developing solutions, various methods have hitherto been proposed. In particular, there have been proposed various additives for accelerating penetration of a color developing agent into coupler-containing oil droplets, where the color developing agent finally undergoes coupling with the coupler to form a dye. Among these additives, benzyl alcohol known to produce a particularly great effect in color formation acceleration, and has been employed for processing of various types of color photographic light-sensitive materials, and is still used widely for processing of color papers.
Since benzyl alcohol has poor solubility, though it is soluble in water to some extent, diethylene glycol, triethylene glycol, or an alkanolamine may be employed in combination to increase the solubility.
However, these compounds and benzyl alcohol itself become a source of pollution when discharged to cause high BOD (biochemical oxygen demand) and COD (Chemical oxygen demand). From the standpoint of waste water disposal, therefore, it has been strongly desired to remove or at least reduce benzyl alcohol despite of the above-described advantages, such as improved color developability or improved solubility.
Moreover, the use of the above-described solvents, e.g., diethylene glycol, is still insufficient to achieve satisfactory solubility of benzyl alcohol, and costs both time and labor for the preparation of a developing solution.
If benzyl alcohol is carried with a developing solution and accumulated in the subsequent belaching or bleach-fix bath, the accumulated benzyl alcohol may form one of causes of leuco compound formation depending on the kind of cyan dyes, ultimately leading to reduction in color density. It is also noted that such accumulation of benzyl alcohol brings insufficiency in washing-away of developing solution components, and particularly a color developing agent, in the washing step. The developing solution components remaining unwashed away result in deterioration of image stability.
From all these considerations, reduction or removal of benzyl alcohol from a color developing solution has a great significance.
In addition to the above-described problems, it has been keenly demanded to shorten a processing time in order to cope with the recent demands of users.
However, conventional techniques failed to fulfill both the aforesaid requirements, i.e., reduction or removal of benzyl alcohol and reduction of a processing time. In other words, reduction of development time combined with removal of benzyl alcohol from a color developing solution has been found to obviously result in serious reduction in color density.
Hitherto various techniques have been reported to shorten a processing time with no or a reduced amount of benzyl alcohol in a color developing solution. For example, Japanese Patent Application (OPI) Nos. 174836/84 and 177553/84 (the term "OPI" as used herein means "unexamined published application") disclose introduction of a specific group into a color coupler and also disclose addition of polyalkylene oxides, or ethers, esters or amine derivatives thereof, thioethers, thiomorpholines, tertiary ammonium salt compounds, urethane derivatives, urea derivatives, imidazole derivatives, 3-pyrazolidones, or the like in a photographic emulsion layer of a photographic light-sensitive material containing the color coupler so as to accelerate the development. This technique is effective for the purpose but is still not satisfactory.